1. Field of the Invention
The present invention generally relates to a to-be-transferred object length measurement device capable of measuring a length of a to-be-transferred object on which an image is transferred, and an image forming apparatus and a computer-readable storage medium.
2. Description of the Related Art
In an image forming apparatus capable of forming a prescribed image while feeding a recording sheet (i.e., a to-be-transferred object) in the sheet feeding path where feeding rollers are provided, there is a known to-be-transferred object length measurement method of measuring a size (length) of the recording sheet as the to-be-transferred object. More specifically, in the to-be-transferred object length measurement method, the size (length) of the recording sheet as the to-be-transferred object is measured by using at least one to-be-transferred object detection sensor provided in the recording sheet feeding path, measuring a time period from when the feeding roller is started to be rotated to when the to-be-transferred object detection sensor detects the passage of the tail end of the recoding sheet, and calculating using the measured time period and the feeding speed of the feeding roller (see, for example, Japanese Patent Application Publication No. 03-172255).
However, the actual feeding speed of the to-be-transferred object may fluctuate due to the change of the diameter of the roller and the like caused by the eccentricity and thermal expansion of the feeding roller and the like to be different from the desired feeding speed. As a result, with the method of measuring the size (length) of the to-be-transferred object based on the measured time period and the feeding speed of the feeding roller, the size (length) of the to-be-transferred object may not be accurately measured.